Add proto output of battery usage stats

Bug: 245832387
Test: adb shell dumpsys batterystats --usage --proto | \
      gqui from rawproto:- proto $ANDROID_BUILD_TOP/frameworks/base/core/proto/android/os/batteryusagestats.proto:android.os.BatteryUsageStatsAtomsProto --protoprint_annotations=no
Change-Id: I297f09892accf0d2adef41d4cbd384a505c9c189